In wireless communication systems, downlink (DL) transmissions such as from a base station (BS) to a mobile station (MS) or subscriber station (SS) may support multiple transmission modes. Performance of the downlink transmissions may be optimized to achieve a specified capacity target by adaptively switching among the multiple transmission modes according the channel of the mobile station and traffic conditions. A feedback channel may be utilized to feed back data relating to a channel quality indicator (CQI) and or other feedback such as information relating to a multiple-input, multiple-output (MIMO) system to support downlink adaptation. In order to optimize overall performance, the feedback channel may be involved in feeding back an appropriate metric for downlink adaptation, reduce feedback latency to allow for robust operation at higher speeds, control feedback to manage uplink efficiency, and/or control feedback reliability to allow downlink optimization.
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